I bought my used S40 recently and wish to get some informatin about the services.

1. When to change the timing belt?
2. When to change the Gear oil?
3. How long for the lifespan on the engine moulding? Distance? I already feel the steerling idling at 60k/mileage. If not mistaken for normal car have 4 unit to handle of engine parts. So, which is the most possible spoilt? I heard many people told me just repair one unit on righthand side. True or false?

4. My car has original alarm system and I heard the volvo orginal parts should have inclusive of Hi-jack system. True or False? If true, then how can I used back the Hi-jack system since I bought it without much of information. There is no instruction manual for the alarm system. Can you tell me more further information if anybody know the system as well.